If someone wants to listen to me call home for grocery store items, or talk to friends about what I did last night, they're free to waste their time. As far as threatening calls and voicemails...I don't pick up the phone for any number I don't recognize, and if anyone's stupid enough to try and make good on a threat, they can tell it to the business end of my 12 guage.
That is scary for sure...Since my cell is main phone I always get nervous when I have to give my credit card info on the cell when I have to update accounts or anything else.
I always get a feeling like I am being tracked when I use my Easy Pass and Sunpass Transponders which in my case is very often..In Florida on the Turnpike some exits are Sunpass Only.
Think how many people use their phone for business use. What info could someone steal or use that they overhead. Or what could suspicious spouses get on each other? (They could hear the whole act in real time and trace where it is coming from)